When Mumford & Sons performed at the iTunes Festival, they probably didn't expect some of the U.K's biggest stars to attend, but that's exactly what happened according to The Sun.

Adele, Chris Martin, Simon Pegg and Emma Watson were all in attendance as the folk-pop quartet bashed out tunes from their latest album, Babel. Company indeed! "We've been all around and now we're home, it feels so good," said Frontman Marcus Mumford. "This is our album launch party, celebrate with us." The band have been touring for years now, and experienced some tough times in some of the far corners of the earth, so they'll be glad to be playing in front of home crowds again. A review of their Roundhouse gig in The Telegraph says: "The show's highlights were when the band loosened their grip on the anthemic jugular. A shimmering Timshel was played unplugged, and the band displayed an enviable mastery of the crowd, who fell deathly silent." Their new album, Babel, which the band describes as "an advert for our live shows" has received mixed reviews, to put it lightly. The Guardian gave their follow up to the incredibly popular debut album, Sign No More, 2 stars. But over in America, where the band is making significant inroads, The Huffington Post described it as "a joy".

The iTunes festival represents 30 days of free music in London, with fans vying for tickets on a competition basis. Acts include One Direction, Lana Del Ray and Plan B.